Mechanism for supporting, raising, and lowering the brushes of vibrating screens



Jan. 11, 1955 E. L. COON MECHANISM FOR SUPPORTING, RAISING AND LOWERING THE BRUSHES OF VIBRATING SCREENS Filed July 23, 1953 I 4 Sheets-Sheet l INVENTOR.

EL Balm 1'12 L. C0012, .1 By W? M ATTORNEY.

Jan. 11, 1955 E. COON 2,699,258

MECHANISM FOR SUPPORTING, RAISING AND LOWERING THE BRUSHES OF VIBRATING SCREENS 4 Sheets-Sheet 2 Filed July 23, 1955 TOR. C0022,

JNVEN L.

ATTORNEY.

Jan. 11, 1955 E. L. COON MECHANISM FOR SUPPORTI NG, RAISING AND LOWERING REENS THE BRUSHES 0F VIBRATING SC Filed July 23, 1955 4 Sheets-Sheet 3 INVENTOR. fidwm L. C0012,

ATTORNEY.

Jan. 11, 1955 coo 2,699,258

MECHANISM FOR SUPPORTI RAISING AND LOWERING THE BRUSHES OF GREENS RATING S Filed July 23, 1953 4 Sheets-Sheet 4 INVENTOR.

Edwin L. C0012, BY

ATTORNEY.

United States Patent MECHANISM FOR SUPPORTING, RAISING, AND gon n nmo THE BRUSHES 0F VIBRATING CR NS Edwin L. Coon, Silver Creek, N. Y., assignor to S. Howes Co., Inc., Silver Creek, N. Y., a corporation of New York Application July 23, 1953, Serial No. 369,751 5 Claims. (Cl. 209-388) This invention relates generally to vibrating screens of the type wherein brushes are arranged under and in contact with each screen unit and are reciprocated relatively to the screen unit or units in order at all times to maintain the meshes open and clear, thereby to avoid blinding at any one or more points and insure efliciency of the screening operation. Such screens are principally used for cleaning or cleaning and grading cereal grains and other seeds, for example, oats, barley, buckwheat, corn, wheat and beans of various kinds.

e brushes include bars or strips commensurate in length with the screen units, the brushes being reciprocated transversely with reference to the direction of reciprocation of the screen units. Upward pressure is applied by springs to the bars of the brushes, thereby to maintain the proper contact of the bristles with the screen fabric.

Two brushes suitably spaced in parallel relation are connected for transverse reciprocation as a unit. Each brush unit is mounted for arrangement in two positions at diiferent elevations, namely a normal upper or active position wherein the bristles engage the screen fabric and a lower or inactive position wherein the bristles are remote from the screen fabric. The inactive position of the brush unit is required when either the associated screen unit or the brush unit requires repair or replacement.

In order to overcome a number of substantial objections to screens of the type described I invented the mechanism for supporting, raising and lowering the brushes whichis shown in Patent No. 2,537,878 of January 9, 1951. While this mechanism very efiiciently serves its purposes as described in said patent it has been found by the experience of use to have objections peculiar to itself.

In my prior construction the brush units follow the screen units in their longitudinal vibration. The movement of the brush units to their active or inactive positions is accomplished by longitudinally arranged cam bars which are carried by the screen shoe and follow the screen units in their longitudinal vibration, the cam bars being manually longitudinally movable relatively to the shoe to either of two positions which respectively determine the active and inactive positions of the brush units. The brushes of each brush unit are connected by cross bars of angle iron form which are mounted for sliding movement upon transverse track rods, the spring pressure which maintains the contact of the bristles with the screen fabric being applied directly to the track rods.

In my prior construction the cam bars are held to the side walls of the shoe by a relation of frictional contact which involves a compromise between that degree of contact which will cause the cam bars to reciprocate with the shoe and that degree of contact which will permit the cam bars to be moved manually longitudinally with respect to the shoe. One objection arising from this characteristic is that in the rapid vibration of the shoe (approximately five hundred complete reciprocations per minute) the cam bars, due to the looseness of theirmounting necessary for their manual longitudinal movement to determine the active or inactive positions of the brush units, set up what may be called a secondary vibration with resultant unnecessary and distractive noise. Another objection, arising from the same characteristic, is that due to the tightness of the mounting of the cam bars necessary for their participation in the vibration of the shoe their manual an undue degree of physical elfort.

In my prior construction the vertical flanges of the angle iron cross bars are required to bear against the transverse track rods in order that there may be no longitudinal play between the brush units and the track bars. The pressure of the springs which is directly applied to the track rods is opposed by the horizontal flanges of the cross bars due to the reaction of the brush units, by means of the bristles, against the screen fabric. For these reasons the cross bars are required to have an undesirable degree of frictional contact with the track rods which produces additional unnecessary noise in the operation of the screen and which also imposes an undesirable power load in the transverse reciprocation of the brush units.

In my prior construction since the brush units follow the longitudinal vibrations of the screen units the movement of the brush units relatively to the screen units is limited to the transverse direction and, as so limited in movement, the brush units require for the efliciency of their action a certain degree of spring pressure with a corresponding pressure of the bristles against the screen fabric and a corresponding rate of wear of the bristles.

The object of the invention is to provide a mechanism for supporting, raising and lowering the brushes of virating screens which will effectively carry out all of the objects set forth in Patent 2,537,878 and at the same time will overcome the objections above pointed out and provide a more etiicient action of the screen brushes with a less degree of spring pressure and hence with a less degree of pressure of the bristles against the screen fabric, thereby increasing the efiicient life of the brushes and reducing the occasions when repair or replacement becomes necessary.

According to the invention the body movement of the brush unit is limited to the transverse direction movement requires the associated screen unit will have components of trans verse and longitudinal direction, that is to say will be in a generally oblique path, with the result that with less spring pressure the brushes will have optimum efliciency in preventing blinding; the brush unit is equipped with rollers which rest and track upon stationary supporting cross rails to which the spring pressure is plied with the results of the brush units is effected with a mmimum of fricnoise; the stationary cross rails are supported for positioning at either of two elevations, the cross rails in their upper positions effecting the engagement of the bristles with the screen fabric and in respect to the bristles having a wear compensating action (upward movement) under the pressure of the associated supporting springs and in their lower positions providing for the spacing of the brushes suitably below the screen fabric, thereby to permit repair or renewal of the brushes or the associated screen unit; and

upon frame carried brackets, spring supporting means for the cross rails and having no participation in the vibratory movement of the shoe and therefore not engendering any noises during or incident to the operation of the screen. These several features in combined relation result in a screen in which extraneous noises are eliminated, an optimum action of the brushes is effected, the useful life of the brushes is substantially prolonged, and the power requirements for the operation of the brushes is substantially reduced.

In the drawings:

Figure 1 is a side elevation of a vibrating screen in which the features of the invention are incorporated.

Figure 2 is a plan view of a brush unit and certain associated parts.

Figure 3 is a longitudinal sectional view on. the line 33 of Figure 2, this figure additionally showing the relation of the brush unit to an associated screen unit.

Figure 4 is an enlarged fragmentary cross sectional view on the line 4-4 of Figure 1, this figure showing one of the side walls of the screen shoe, adjacent parts of the brush unit and the screen unit, one of the cross cooperating with the rails for the support of the brush unit, the spring means for the support of the cross bar, and the rock shaft and cam means for positioning of the cross rail in accordance with the active or inactive phases of the brush unit.

Figure 5 is a fragmentary sectional view on the line 5--5 of Figure 4.

Figure 6 is a detail fragmentary perspective view showing one of the supporting rails for the brush units together with cam mechanism associated with each end portion of the rail for determining the active or inactive position of the brush unit.

Figure 7 is a perspective view showing the features of construction involved in the relation between a brush and an associated supporting cross rail.

In respects other than the features of the invention the vibrating screen conforms to standard practice. It embodies a main frame having vertical side elements 1, the usual vibratory shoe 2, one or more screen units 3, and a brush unit 4 in operative association with each screen unit. The frame 5 of a screen unit may be made in two or more panels and carries the usual screen fabric 6. The frames 5 are mounted to participate in the vibration of the shoe. The brushes are of the so-called strip type, i. e. wherein the bristles are mounted on bars or strips commensurate in length with the screens. The brushes are preferably of the construction shown in Patent 2,510,741 of June 6. 1950, and include an elongated supporting member 7 of angle iron cross section having a horizontal flange 8 and a vertical flange 9. The bristles 10 are mounted in holders 11 which are clamped to the supporting member 7, the clamps being constituted by the vertical flange 9 of the member 7 and by clamping members 12 of general ogee 0r Z-shaped cross section.

In accordance with standard practice the shoe is supported for reciprocatory vibration in the general direction of its length by means of any suitable motor driven mechanism 13, the mechanism selected for schematic illustration being substantially of the construction shown in the patent to Roth No. 1,517,587 of December 2, 1924 (currently known in the industry as the Buhler Drive).

In accordance with standard practice each brush unit consists of two parallel brushes connected by a centrally located tie rod 14 and cross bars 15 located near the ends of the members 7, the brush unit being reciprocated in a transverse direction during the vibration of the shoe. The standard means for reciprocating the brushes is sufficiently indicated by the showing of the sprocket chain 16 (Figure 1) and the clevises 17 (Figure 2) at the opposite sides of the brush unit to which the chain 16 is connected, the chain 16 being operated by suitable gearing from the main drive shaft 13a.

The brush unit is supported for transverse reciprocation upon two relatively stationary cross rails 18 located respectively adjacent the front and rear ends of the screen. Two angle pieces 19, one corresponding to each cross rail. are connected, preferably by welding, to the horizontal flange 8 of each brush supporting member 7 and are located to project laterally inward beyond the member 7. The vertical flange of each angle piece 19 carries a bracket 20 which is provided with a pair of parallel vertical cars 21 projecting laterally inward beyond the piece 19. Each pair of ears 21 accommodates and supports a roller 22 having an axle 23 journalled in the ears, the rollers 22 tracking upon the cross rails 18. In order that the brush units may be held against displacement in the longitudinal direction of the screen each roller 22 is provided with a terminal flange 24. The flanges 24 of the two pairs of rollers are located at relatively opposite sides of the two cross rails 18. For example the flanges of the front and rear pairs of rollers 23 are adjacent the rear and front sides of the respective front and rear cross rails 18.

In the construction shown and preferred the cross rails 18 each include a body 25 of inverted channel or U-shape in cross section which has a flat top wall 26 upon which the rollers 22 track and parallel vertical side walls 27, each having along its lower edge an inturned portion 28 which provides a shoulder extending lengthwise of the body. Each cross rail also includes straight lengthwise extensions 29 projecting from the ends of the bodies 25 and having parts 30 located within the channels defined by the bodies 25. The parts 30 rest upon and are held tightly against plates 31 which are supported by tion of vibration.

the shoulders 28. The extensions 29 are held against lengthwise movement relatively to the bodies 25 by fastening bolts 32 which extend through the space between the walls 27 and are tapped into openings extending from the lower face of the parts 30, the bolts 32 passing through openings in the plates 31. The heads 33 of the bolts 32 engage clamping plates 34 located externally of the body 25 and bearing against the lower edges of the Walls 27. It will be noted that the extensions 29 are lengthwise positionally adjustable with relation to the bodies 25. Thereby the bodies 25 may be made of a standard length and the cross rails as a whole (bodies 25 and extensions 29) may be made to conform in length to the width of the particular screen as measured by the mutual spacing of the frame side elements 1. For the purpose of such positional adjustment all that is required is to back off the bolts 32 to release the clamping pressure of the plates 34 and to slide the parts 29 inwardly o r outwardly relatively to the bodies 25 until the cross rail has the desired length whereupon the bolts 32 are 'tight ened to cause the plates 34 to bear with clamping pressure against the lower edges of the walls 27.

The cross rails 18 extend through openings 35 in the side walls of the shoe 2 (Figures 4 and 5) and through openings 36 in the frame side elements 1. The vertical extent of the openings 35 and 36 is such as to permit the movement of the rails 18 from the raised active positions in which they are shown in full lines in Figure 4 to their lowered inactive positions as indicated by the broken lines X in Figure 4. The longitudinal extent of the openings 35 is such as to permit the shoe 2 to have its vibratory stroke with the rails 18 held in a fixed plane normal to the direction of vibration.

The rails 18 are supported at each end by helical coil springs 37 which act upon them through depending posts 38. The upper portions of the posts 38 are tapped into openings in the extensions 29 and the posts are held against movement relatively to the extensions by suitable loek nuts 38a which bear against the lower faces of the extensions. Each spring 37 and associated post 38 are elements of a rail supporting unit which includes a bracket 39 adjacent the outer face of the associated frame side element 1, the bracket 39 being secured to the frame side element 1 by bolt fastenings 40 and having an opening 41 which registers with the opening 36. Either or both of the openings 41 and 36 may be in the form of slots which conform in width to the width of the extension 29 which passes through them, the rails 18 being thereby held in a fixed plane normal to the direc- The bracket 39 is provided at its lower end with an outwardly projecting shelf 42 upon which the spring 37 rests. The post 38 projects through the spring 37 and through an opening in the shelf 42 and carries upon its upper threaded portion a nut 43 which provides a shoulder to receive the thrust of the spring 37. Thereby the rails 18 are pressed upwardly to a position which is limited by the engagement of the bristles 10 against the screen fabric 6. Wear of the bristles 10 is compensated by the upward pressure of the springs 37 upon the rails 18. The nuts 43 are positionally adjustable to regulate the degree of pressure exerted by the springs 37.

The movement of the rails 18 to their lower positions X (the inactive position of the brush unit) is effected by eccentric cams 44 which are provided at each side of the screen and bear upon the extensions 29. The two cams 44 for each brush unit at each side of the screen are fixed upon a longitudinal rock shaft 45. The shafts 45 are journaled in outwardly projecting arms 46 carried by the brackets 39 and are held against displacement in the direction of their axes. Each shaft 45 is provided at its front end with a handle 47 by which it may be turned. In the active position of the brush units the handles 47 extend vertically downward from the shafts 45 as shown in Figure 4 and the earns 44 rest idly upon the extensions 29, opposing no resistance to the upward displacement of the rails 18 by the springs 37.

When a brush unit is to be moved to its lowered inactive position X the shafts 45 are turned by their handles 47 through a suitable angle sufficiently indicated in Figure 4 by the broken lines Y which show the positions of the handles 47 at the completion of the turning movement of the shafts 45. In such turning movement of the shafts 45 the cams 44 are moved downward and, engaging the upper faces of the extensions 29, move the rails 18 to the positions X in which the brush units are fully lowered. The downward 44 are continued slightly beyond dead center and thereby positively latch positions. The downward movements of the cams 44 are limited to the positions Z by stop pins 48 which project upward from the extensions 29 at the outer ends thereof. With the brush unit held in its lowered inactive position the repairs to the brushes or screen units are made in the usual manner. When the repairs have been completed the handles 47 are moved downward from the positions Y and the cams 44 are moved inwardly from the positions Z, thereby releasing the rails 18 for upward movement in response to the pressure of the springs 37, such upward movement of the rails restoring the brush units to their active positions as shown in Figure 4.

I claim:

1. In a vibrating screen of the type which includes a stationary supporting frame having vertical side elea vibratory shoe having side walls and mounted between the side elements ot the frame, means for etfecting longitudinal vibration of the shoe, a screen unit carried by and vibratory with the shoe and consisting of a frame and screen fabric, connected brushes of the strip type extending longitudinally of the screen unit adjacent each side thereof and having bristles which normally bear with pressure against the underface of the screen fabric, the brushes being substantially coextensive in length with the screen unit, and means for reciprocating the brushes transversely of the screen unit during its longitudinal vibration with the shoe: mechanism for supporting, raising and lowering the brushes comprising, in combination, cross rails extending between and under the brushes, brackets carried by the brushes, rollers carried by the brackets and resting and tracking upon the cross rails, the rollers engaging the cross rails in a manner to prevent the movement of the brushes with the screen unit in its vibration, the side walls of the shoe having openings through which the cross rails project laterally, a pair of units for the support of each cross rail, one unit being located at each side of the screen, each cross rail supporting unit comprising a bracket fixed to a vertical side element of the frame and having an opening through which the cross rail projects laterally, the opening in the frame-carried bracket conforming in width to the width of the cross rail, thereby to maintain the cross rail in a fixed plane normal to the direction of vibration of the screen unit, a helical coil spring supported by the frame-carried bracket and acting from below upon the laterally projecting part of the cross rail, thereby to apply upward pressure to the cross rail, and a movably mounted manually operated cam carried by the framecarried bracket and acting from above upon the projecting part of the cross rail, the cam having two positions in one of which it opposes no resistance to the upward thrust of the spring and in the other of which it holds the cross rail in a lowered position in which the brush bristles are spaced from and below the screen fabric, the openings in the side Walls of the shoe and in the frame carried bracket being dimensioned to permit the movement of the cross rail between its raised and lowered positions in response to the movement of the cams and the openings in the side Walls of the shoe being also dimensioned to permit the reciprocatory vibration of the shoe with the cross rail held in the said fixed. plane.

2. Mechanism for supporting, raising and lowering the brushes of vibrating screens as set forth in claim 1 wherein the cams in e 'ecting the movement of a cross rail to its lowered position are rockably mounted and are movable downward to positions slightly beyond dead center, thereby positively to latch the cross rails in their lowered positions, and the cross rails are provided with means for limiting the downward movement of the cams to their latching positions.

3. Mechanism for supporting, raising and lowering the brushes of vibrating screens as set forth in claim 1 wherein each cross rail has a body of determined length and channel-shaped section to provide an upper wall upon which the rollers track and depending side walls, and the cross rails include straight extensions which project from the body and have parts fitted within the body, the extensions being positionally adjustable relatively to and lengthwise of the body, and means is provided in cooperation with the extension parts fitted within the body for fixing the extensions relatively to the body in any position to which they may be adjusted, thereby to conform the length of the cross rail to the width of the screen.

4. Mechanism for supporting, raising and lowering the brushes of vibrating screens as set forth in claim 1 wherein the cams at each side of the screen are mounted upon a manually operated rock shaft and the frame carried No references cited. 

